1. Field of the Invention
This invention relates to a cylindrical wheel speed sensor and, more specifically, to a mounting device for such a sensor which enables the sensor to be utilized in a variety of wheel configurations while maintaining accurate positioning thereof for reliable operation.
2. Description of the Prior Art
Modern anti-lock vehicle brake control systems operate in response to electrical signals indicative of the angular velocity of one or more of the vehicle wheels. Usually these signals are derived from an electromagnetic sensor, including a magnet carried by a stationary portion of the vehicle such as the axle housing and a toothed or notched metal ring which rotates with the wheel opposite the magnet. As the ring teeth pass the magnetic sensor device, the resulting variations in flux produce a voltage, the frequency of which is a function of the angular velocity of the wheel and number of teeth in the ring.
To produce the required voltage level of the velocity signal, the sensor and ring must be accurately located with respect to each other during initial assembly and must remain in a preselected relationship even after extended operation in which the components are subjected to road shocks and constant vibration. It is also essential that installation of the sensor assembly be accomplished in a manner adaptable to mass production methods to minimize the need for skilled technicians and elaborate installation techniques.
Further, to satisfy an ever increasing demand for brake control systems, it has become necessary to provide sensor-rotor systems to a variety of existing wheel configurations. Consequently, to simplify and standardize the sensors, a generally cylindrical housing has been provided which has overall dimensions to accommodate installation at various locations as desired for the particular wheel assembly. The means for mounting this sensor must insure that the above mentioned relationships can be obtained during installation and retained during vehicle operation.
There have heretofore been utilized wheel speed sensors, such as those disclosed in U.S. Pat. Nos. 3,769,534, 3,772,548, 3,772,549, and 3,774,061, in an effort to provide overall configurations which satisfy some of the above stated requirements.